Tensioners for timing belts, timing chains and accessory drive belts are well known. Some tensioners are adjustable in terms of the amount of tension is generated in the belt during operation of the engine. Such tensioners react to certain sensed conditions that indicate a potential for, or occurrence of, belt slip. While such systems may reduce the frequency of belt slip, they are, by design, inherently permitting some belt slip to occur. In those systems that sense the actual occurrence of belt slip, belt slip has already necessarily occurred before the tensioner will increase belt tension. In systems where the conditions for belt slip are sensed, the conditions that create the potential for belt slip must already occur for them to be sensed by the tensioner, which inherently means therefore that belt slip can occur before the tensioner has reacted to increase belt tension.
While these systems have some advantage in terms of reducing the frequency of belt slip, they still permit some belt slip to occur, which may be detrimental to the belt, to certain accessories driven by the belt, and to the perception of low quality of the vehicle by a person hearing the chirp that can accompany belt slip.
Furthermore, the tension adjustment mechanisms employed by such tensioning systems may be expensive, and/or unreliable.
It would be beneficial to provide a tensioning system that has at least partially addresses one or more of these problems.